Process for polymerizing cf=cfci in slurry system



April 17, 1956 J. s. REARlcK Erm.

PROCESS F'OR POLYMERIZING CP2 CFC, IN SLURRY SYSTEMS Filed Sept. l5, 1952 kw. NM.

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United States PatentOe 2,742,454' Patented Apr. 17, 1956 PROCESS FOR POLYMERIZING CFziCFCl IN SLURRY SYSTEM Jhn s: Resnick, Dover, and Reben P. schaar, East Orange, N. J., assignors to The M. W. Kellogg Company, IJerseyCity, N. J., a corporation of Delaware Application September 13, 19572, Serial No. 309,434`

` s claims. (cuen-42.1)

polytriiluorochloroethylene. In employing distillation to purify the monomer it was found substantially impossible to remove the last traces of the methanol because it formed an azeotrope with monomer. The methanol contamina tion of the monomer aiected the chemical and physical characteristics of the ultimate polymer and results in a polymer of inferior characteristics. The presence of said contaminant also adversely aiected the rate of polymerization and the yieldof polymer therefrom. Handling of the polymerizationY mixture during polymerization presented a `problem because of the high viscosity of the monomer-polymer slurry. The monomer-polymerslurry is very dicult to circulate in the polymerization zone and during subsequent recovery steps. The high viscosity of the monomer slurry was due primarily to the high absorption of monomer in the solid polymer.` The recovery of solid polymer from monomer by filtration is also ditlicult because of the high absorption of monomer in solid polymer. It is, therefore, the purpose of this invention to overcome the above diiculties of both the bomb type of operation and previously proposed conable promoter and the ytemperature of the bomb is maintained at about- 16 C. or 17 C. for a period of about seven days.` VIrrthis time the monomer is polymerized to form aporous plugof solid polymer in thereaction bomb with approximately 30, to 50 per cent yield of polymer based on monomerV charged. The unreacted monomer isv occluded in the interstices of the'porous plug and is removed .therefrom byheating the reaction bomb under subatmospheric pressure to evaporate unreacted monomer. 'y The dried porous plug vofv polymer kof triuoro chloroethylene is removed from ythe .reaction vessel and broken into chips orgranules for shipment in handling.

-. The bombA reactor is about 6 inches in diameter ,and is placed in a liquid cooling bath. Larger diameter bombs cannot be used -because of--the poor heat transfer of the monomer and solid polymer. v 5 -The bomb type of operation for the production of solid polymers of triuorochloroethylene and other, perhalo-- genated olens has its inherent disadvantages. The apparatusand equipment is cumbersome with relatively low capacity. The accompanying labor costs are high. However, ythe yield of product based on monomer is high and the purity and physical characteristics of the resulting polymer are exceptionally good providing the monomer s.. adequately puriled. v To overcome the low capacity andy high labor,k costs forthe. polymerization of triuoroc'hloroethylene in the bomb type reactors, continuous slurry type methods have beenproposed. In such previously proposed continuous process the monomer is produced by dechlorination of triuorotrichloroethane by zinc in the presence of methanol. The crude monomerfrom the dechlorination still is then passed through a series of distillation columns to remove thev high boiling contaminants of the crude monomer. Purified monomer is recovered Vfrom the overhead from the last distillation column. The distilled monomer is then contacted with an appropriate absorption medium to remove the last trace of methanol and 'any watery that may be present. According to such continuous process, the monomer is then polymerized in an autoclave type of reaction vessel and a slurry of monomer andsolid polymer is withdrawn-from the autoclave and Asubjected to filtration to remove polymer from monomer andy drying tolremove the last traces of occluded monomer lfrom the solid. polymer. Certain disadvantages have been found in the above proposed'continuous process for the production of solid tinuous type of operation as described above.

The object of this invention is to provide a continuous process for the polymerization of perhalogenated olefins to -producc normally solid homopolymers and copolymers.

Another object of this invention is to provide a method for purifying monomer. l

4Another object of this invention is to provide a method for recovering dried solid polymer from a monomer slurry thereof. i

Thereis still a further object of this invention to provide an integrated continuous process for the puriication of monomer, polymerization of the monomer to produce a solid polymer and the recovery of monomer from solid polymer product. v A further object of this invention is to provide a processfor large capacity production of normally solid polymers of triuorochloroethylene, such as the thermoplastic polymer having an N. S. T. between about 240 C. and about 350 C.

Yet another object of this invention is to provide a continuous process for the polymerization of triuorochloroethylene whereby the costs of production are substantially decreased.

Various other objects and advantages of the .present invention will become apparent to those skilled in the art from the accompanying description and disclosure.l

This invention applies generally to the polymerization of perhalogenated oletns to produce both solid homopolymers and copolymers. A perhalo olefin is deiined asan olefin consisting of carbon and halogen with any degree of unsaturaton; preferably according to this invention, the'perhalo olefin contains fluorine, or chlorine, or both as the halogens. According to this invention a saturated iluorochloro carbon is dechlorinated under suitable conditions of dechlorination in the presence of a metallic dehalogenating agent to produce a pertluorohalomonooleiinjas a monomer for subsequent polymerization. The dechlorination is carried out in the presence of a suitable solvent, such as methanol or ethanol. The crude monomerveffluent containing both higher boiling and lower boiling contaminants is removed from the dechlon'nation reactorandupuried. lThe major contaminants of the crude monomer arethe solvent, such as methanol, and other perhalo oletins or vperhalo paratlins. Accordingly, the crude monomer is water washed to eiectively remove substantially all of the methanol or water soluble solvent. After water washing, the. water Washedl monomer isv then dried under conditions such that the monomer Contains less than about p. p. m., preferably less rthan l0 p, p. m. of water, and distilled to remove low boiling impurities. After removal of the low boiling impurities the monomer bottoms from the rst distillation is subjected to a second distillation to remove the high boiling impurities. Best results are obtained by distillation at pressures above 100 pounds per square inch gage. Thereafter, the purified monomer is polymerized in a horizontal tlow elongated reactor to form a slurry of solid polymer and monomer having a concentration not more than about 12 weight per cent polymer in monomer. The polymerization is effected generally at a temperature between about F. and about 60 F. or 70 F. under liquid phase conditions for a period of time between about 2 and about 40 hours. The slurry of polymer and monomer is then dried at an elevated temperature above about 150 F.to recover the polymer. The solid polymer is recovered as a product of the process. At least a portion of the recovered monomer is recycled to purication step to prevent the build up of impurities in the recycle. y

The present invention is applicable to the homopolymerization of triuorochloroethylene and to the copolymerization of trilluorochloroethylene with other halogenated fiuorine containing olens having no more hydrogen atoms than the number of carbon atoms. Such copolymerizations include the copolymerization of triuorochloroethylene with tetrauoroethylene, peruoropropene, periluorobutadiene, vinylidene fluoride, trifluoroethylene, monouorochloroethylene, monouorotrichloroethylene and ditiuorodichloropropene. In the copolymerization it is usually preferred to employ between about 5 and 95 weight per cent of comonomer with truorochloroethylene. The conditions of polymerization of the copolymers of triuorochloroethylene are substantially the same as for the homopolymerization of triuorochloroethylene. The following discussion of the general application of the present invention to the polymerization of triuorochloroethylene applies substantially to all copolymerization systems with tritluorochloroethylene.

For a better understanding of the present invention reference will be made to the accompanying drawing which diagrammatically illustrates a suitable arrangement of apparatus in elevation which is used for the production of normally solid plastic homopolymers and copolymers of triiluorochloroethylene. The principal pieces of apparatus for effecting the process depicted in the drawing comprise a dehalogenator 12, a water wash tower 24, distillation columns 38 and 43, polymerization reactor 58, spray dryer 71, cyclone separator 73 and concentrator 103. The process will be described in the drawing for the polymerization of trilluorochloroethylene to produce the homopolymer thereof. lt will be understood that the quantities and other operating conditions referred to are for purposes of illustration and may be varied without departing from the scope of the invention.

According to the drawing and the process illustrated, triuorotrichloroethane of the 1,2,2, chloro structure, which may be obtained commercially on the open market as Freon ll, is passed through conduit 11 to dehalogenator 12. A metallic dechlorinating agent, such as zinc dust, is introduced into dehalogenator 12 through means not shown. Although zinc is preferred various metal dechlorinating agents may be used, such at tin, manganese, magnesium and'iron without departing from the scope of this invention. A suitable solvent or diluent is introduced into dehalogenator 12 through conduit 11. The preferred solvent is methanol. However, ethanol has also shown good results and there are various other conventional solvents for use in such a process. The mixture of tritluorotrichloroethane, solvent and zinc is vigorouslyI agitated by conventional means, such as a stirrer, as shown. Dehalogenator 12 is maintained at a pressure of about 150 pounds per square inch gage and at a temperature of about 210 F. The temperature conditions are produced initially by steam in the jacket of the reactor. Once the reaction has been initiated it is self sustaining and cooling water is used in the jacket to control the reaction. Under these conditions Freon 113 is dechlorinated to triuorochloroethylene which is passed overhead through dephlegmator 13 which removes a portion of entrained and vaporized methanol Freon 113 and other contaminants. The crude monomer is passed through conduit 14, condenser 16 to accumulator 17. The temperature of the material leaving dephlegmator 13 is approximately 110 F. and is reduced to a temperature of approximately F. by conventional cooler 1. The pressure in accumulator 17 is approximately 150 pounds per square inch gage. A portion of condensate in accumulator 17 is recycled to dephlegmator 13 as reflux through conduit 18. Zinc chloride and the bottoms from the reaction in dehalogenator 12 may be removed therefrom through conduit 21. Conduit 19 is for the purpose of venting accumulator 17 to prevent the build up of pressure in the system.

Approximately 380 pounds per hour of monomer is passed from accumulator 17 through conduit 22 by means of pump 23 to the upper portion of water wash tower 24. Deaerated water is introduced into the bottom of tower 24 through conduit 25 at a rate of about 350 pounds per hour and. countercurrently contacts downflowing liquid monomer. Washed liquid monomer substantially free from methanol is passed through conduit 26 to dryers 34 and 36 containing calcium sulfate. Dryers 34 and 36 may contain any conventional type of drying material, such as disclosed in Patent No. 2,600,804. 'The wash water is removed from the upper portion of tower 24 `through conduit 27 and is passed to accumulator or sepa-` rator 28. About 350 pounds per hour of water is removed from separator 28 through conduit 29. This water contains dissolved methanol. Any entrained or dissolved monomer is removed from the upper portion of accumulator 28 as vapor through conduit 31 and is passed to dryer 32 containing calcium sulfate. The dried monomer vapor is then recycled through conduit 33. The water washed and dried liquid monomer from the bottom of tower 24 is passed through conduit 37 to the intermediate portion of a distillation column 38. This monomer stream contains on an hourly basis approximately 691 pounds of monomer, 2.46 pounds of triuoroethylene, 2.96 of dilluorovinyl chloride and 2.58 pounds of trichloromonoiiuoromethane. In distillation column 38, separation is made between monomer and lower boiling impurities, such as triuoroethylene together with minor amounts of other impurities. Conventional reboiler 39 maintains the bottom temperature of tower 38 at about 125 F. Liquid monomer substantially free from tritluoroethylene is removed from tower 38 through conduit 41. The vaporous overhead fraction from tower 38 containing monomer, triuoroethylene and minor amounts of other light impurities is removed therefrom through conduit 42 and is passed through a conventional cooling means 43 to an accumulator 44. The temperature and pressure maintained in accumulator 44 are about 170 pounds per square inch gage and 80 F. Uncondensables may be vented through conduit 48, it necessary. Approximately 706 pounds of the overhead fraction is recycled as reflux from accumulator 44 to distillation tower 38 through conduit 46. Approximately 2.46 pounds per hour of triuoroethylene and approximately 2.34 pounds per hour of monomer are recovered from accumulator 44 through conduit 47. The top temperature of distillation tower 38 is maintained at about 94 F.

The liquid monomer stream in conduit 41 is substantially free from tritluoroethylene and light impurities but contains diuorovinyl chloride, trichlorornonouoromethane and higher boiling impurities. This stream is passed through conduits 41 and/or 45 into the intermediate portion of a distillation tower 50. Element 60 is a reboiler which maintains a bottom temperature of about F. in tower 50. A liquid bottoms fraction comprising about 4.66 pounds of monomer, about 2.96 pounds of diuoro vinyl chloride, about 7.38 pounds of trichloromonouoromethane per hour and minor amounts of heavy impurities is removed from tower 50 through or recovery. Y

A vaporous overhead fraction is removed from distillation tower 50 through conduit 55 and is passed through a conventional cooler 70 to an accumulator 49. Accumulator 49 is maintained at a pressure of about 160 pounds per square inch gage and at a temperature of about 120 F. Av portion of the condensate-is recycled vthroughv conduit 51 tothe upper portion of distillation tower 50.y r[,his reflux stream amounts to about 7,966 pounds perhour of monomer. A stream of substantially pure monomer is passed through conduit 52 throu'gha conventionaljcooler 53 to a feed accumulator 54. `About684 poundsper' hour of monomer is passed through conduit'52 at'f32"F. to accumulator 54. Accumulator 54' is maintained at a temperature of about 32 F. and a pressure of` about 30 pounds per square inch gage. Liquid feed monomer is passed from accumulator 54 through conduit 56 to the lower portion of a horizontal-polymerization chamber 58. A promoter, such as trichloroacetyl peroxide, is introduced as a solution of appropriate strength-in4v trichloromono` fluoromethane into feed conduit 56.' About 7.6 pounds per hour of such solution is introducedt'hrough conduit Polymerization chamber 58-comprises a horizontal cylindrical chamber containing'bales 61 v dividing the chamber into three sections. The monomer polymer slurry in chamber 58 is maintained in a state ofagitaton` in each of the polymerization ysections by conventional stirrers 59. The bottom of batlles 61`c'ontains openings so that the monomer polymer mixture may ow horizontally from the entrance of chamber 58 to the exit thereof'. The liquid level in chamber 58 is maintained just below the top of bafes 61. A monomer polymer slurry "containing less' than about l2 per cent fsolid polymer,A preferably about to 7 per cent polymer, iswithdrawn from the other end of horizontal chamber 58"'through conduit 62. Chamber 58 is maintained at a pressure of about 30 pounds per square inch gage and a temperature of about 32 F. Under these conditions monomer is vporized due to heat evolved in the reaction and is removed 4from the' open space at the top of chamber 58 throughv a conduit 63 and is passed through conduit 64 to a conventional condenser 66. From condenser 66 liquid monomer vis 'recycled through conduits 67 and 52 to accumulator l54. Any monomer vapor evolved from"accu'rnulator S4 isv also passed to condenser 66 through conduit 64. The amount of monomer recycled through conduits 63 and 64 is about 2,030 pounds per hour at 32 F. The vap'orizaton'v of this monomer in accumulator 54 and chamber 58 maintains the temperature of polymerization in "chamber'SS, and the heat of polymerization is removedby condenser 66. Uncondensed vapors are removed from the top of condenser 66 through conduit 68 and are recycled, :as shown.

About 2,680 pounds per hour of liquid monomer and about 171 pounds per hour of solid; polymer :are passed through conduit 62 and pump 69 into spray dryer 71. The outlet temperature of sprayv dryer 71 is maintained at about 150 F. Vaporized monomerand suspended nely divided solid polyme'i are passed from spraydryer 71 through conduit 72 to cyclone separator 71'.` In cyclone separator 73 solid polymer is separatedy from vaporized monomer. Vaporized monomer isrecycled to spray dryer 71 through conduit 74 through Yheater 77by means of blower 76. Dried polymer isl passed from cyclone separator 73 alternately Vthrough conduits 78 and' 79 to lock hoppers 81 and 82, respectively.' The lock hoppers are used alternately; when one lockhopper is filled, it is emptied by passing solid polymer through conduit 83 to screw conveyor 86 to storage hopper 87. Solid polymer product is recovered from storage hopper 87 through conduit 89 at a rate of about 171 pounds per hour. This material is passed through conventional extrusionapparatus for extruding the polymer for preparation for packing and shipping. While hopper 82 is being emptied hopconduit 75 for disposal per v81 is being `filled and, vice versa, when hopper 81 is' being emptied through conduit 84 hopper 82 is being lled.

Prior to emptying the hoppers 81 and 82,.-vaporzed monomer is passed through conduits 91, 92 and 93 to dryer 96.y Dryer 96 contains calcium sulfate `or other conventional absorbing material to remove impurities so that the impurities will not coirode compressor 97 which is used to compress the monomer for introduction into conduit 68 for recycling. After emptying, lock hoppers 81 `and 82 are repressured with Vnitrogen through conduit 94. v The temperature of vaporous monomer from compressor 97s about 300 F.` ,Monomerlis divided from conduit74 and a portion passed thro-ugh conduit 100 at about 150 F. fthrough cooler 102, where thev temperature is reduced to about 100 F., to monomer scrubber and concentrator 103. Vaporized monomer containing entrained finely divided polymer is introduced into the bottom of scrubber 103. About 2,680 pounds per hour of monomer is passed through conduit 100 to scrubber 103.l Scrubber 103 contains a condensing or cooling element 105 in the top thereof to condense upwardly flowing monomer, lwhich then ows as liquid to the bottom of scrubber 103. Scrubber 103 is maintained at a pressure of about 35 pounds per square inch gage and about 40 F. Liquid monomer is recycled by means of pump 107 through conduit 106 to the upper portionfof scrubber 103 to scrub solids from the vaporous monomer. The liquid inthe bottom of scrubber 103 contains nely divided polymer recovered in concentrated forml and is recycled through conduit 104 to conduit 56 for `return to polymerization vessel 5S. The amount of monomer thus returned is approximately 2,167 pounds per hour through conduit 104. The temperature of this stream is about 32 F: About-320 pounds per hour of the liquid monomer in the bottom ofI scrubber 103 is passed through conduit 108 by means of pump 109 to conduit 22 for repuriiication. Vaporized monomer from scrubber 103 is passed to conduit 68. vThe'vaporous monomer in conduit 68 is passed through absorber 98 containing calcium sulfate. This absorber is used to remove contaminants which might corrode subsequent compressor 99. From-absorber 98, vaporous monomer is passed through'conduit 68 by means of compressor 99 at a rate of about 193 pounds per hour and pounds per square inch gage and at a temperature of 240 F. through cooler 101 to accumulator 17. Cooler 101 cools the monomer to about 100 F.

The conditions of operation of dehalogenator 12 and polymerization chamber 5S, including the types of promoters and solvents, may be carried out in accordance with the vteachings of Patent No. 2,600,804. Although different reaction conditions may be employed, such as temperature in chamber 58, if the reaction conditions are changed, the pressure and temperature conditions in the entire system is changed accordingly. Various modifications of the materials used and operating conditions may be employed without departing from the scope of this invention. However, the method of purification, type of polymerization zone and method of recovery of the product are essential features of the' present invention and the integration of these features into a single unitary and continuous process is part of this invention.

Having described our invention, we claim:

1. A process for polymerizing tritluorochloroethylene to produce a solid polymer which comprises introducing triuorochloroethylene into one end of a horizontal elongated reaction zone maintained at a temperature of about 32 F. and a pressure of about 30 pounds per square inch gage, polymerizing monomer in said reaction zone to solid polymer to form a slurry containing not more than 12 per cent solid polymer, flowing said polymer slurry horizontally through said reaction zone, removing monomer vapors from said reaction zone, cooling and condensing said monomer vapors thus yremoved and returning condensate to said reaction zone to control the temperature thereof,- removing monomer-polymer slurry from the other end of said reaction zone, passing a slurry containing monomer and solid polymer from said reaction zone to a spray drying zone, spray drying the monomer slurry at a temperature at least about 150 F. to form inely divided solid polymer in monomer vapor, separating solid polymer fro1nrnonomer vapor and recovering solid polymer as a product of the process, returning a portion of the aforesaid monomer vapor to said drying zone at an elevated temperature to aid in the drying of said slurry, passing another portion of the aforesaid vaporous monomer containing entrained solid polymer to a concentration zone, in said concentration zone contacting vaporous monomer containing entrained solid polymer with liquid monomer, and recovering a liquid condensate containing solid polymer and recycling same to said horizontal reaction zone.

-2. A process for polymerizing triiluorochloroethylene to produce a solid polymer which comprises introducing triluorochloroethylene into one end of a horizontal elongated reaction zone maintained at a temperature of about 32 F. and a pressure of about 30 pounds per square inch gage, polymerizing monomer in said reaction zone to solid polymer to form a slurry containing not more than l2 per cent solid polymer, owing said polymer slurry horizontally through said reaction zone removing monomer vapors from said reaction zone, cooling and condensing said monomer vapors thus removed and returning condensate to said reaction zone to control the temperature thereof, removing monomer-polymer slurry from the other end of said reaction zone, passing a slurry containing monomer and solid polymer from said reaction zone to a spray drying zone, spray drying the monomer slurry at a temperature at least about 150 F. to form finely divided solid polymer in monomer vapor, separating solid polymer from monomer vapor and recovering solid polymer as a product of the process, and returning a portion of the aforesaid monomer vapor to said drying zone at an elevated temperature to aid in the drying of said slurry.

3. A process for polymerizing triuorochloroethylene to produce a solid polymer which comprises introducing triuorochloroethylene into one end of a horizontal elongated reaction zone, polymerizing monomer in said reaction zone to solid polymer to form a slurry containing not more than l2 per cent solid polymer, flowing said polymer slurry through said reaction zone, removing monomer vapors from said reaction zone, cooling and condensing said monomer vapors thus removed and returning condensate to said reaction zone to control the temperature thereof, removing monomer-polymer slurry from the other end of said reaction zone, passing a slurry containing monomer and solid polymer from said reaction zone to a spray drying zone, spray drying the monomer slurry to form iinely divided solid polymer in monomer vapor, separating solid polymer from monomer Vapor and recovering solid polymer as a product of the process, returning a portion of the aforesaid monomer vapor to said drying zone at an elevated temperature to aid in the drying of said slurry, passing another portion of the aforesaid vaporous monomer containing entrained solid polymer to a concentration zone, in said concentration zone contacting vaporous monomer containing entrained solid polymer with liquid monomer, and recovering a liquid condensate containing solid polymer and recycling same to said horizontal reaction zone.

4. A process for polymerizing triiluorochloroethylene to produce a solid polymer which comprises introducing triuorochloroethylene into one end of a horizontal elongated reaction zone maintained polymerizing monomer in said reaction zone to solid polymer to form a slurry containing not more than l2 per cent solid polymer, flowing said polymer slurry through said reaction zone, removing monomer vapors from said reaction zone, cooling and condensing said `monomer vapors thus removed and returning condensate to said reaction zone to control the temperature thereofl -removing monomer-polymer slurry from the other end of said reaction zone, passing a slurry containing monomer and solid polymer from said reaction zone to a spray drying zone, spray drying the monomer slurry to form finely divided solid polymer in monomer vapor, separating solidpolymer from monomer vapor and recovering solid polymer as a product of the process, and returning a portion of the aforesaid monomer vapor to said drying zone at an elevated temperature to aid in the drying of said slurry.

5. A process for polymerizing tritiuorochloroethylene to produce a solid polymer which comprises introducing a puried triuorochloroethylene monomer stream to one end of a horizontalelongated reaction zone maintained at a temperature between about 0 F. and about 60 F. and a pressure sufcient to maintain the monomer in liquid phase, polymerizing monomer in said reaction zone to a solid polymer to form a slurry containing not more than about 12 per cent solid polymer, flowing said polymer slurry through said reaction zone, removing monomerpolymer slurry fromthe other end of said reaction zone, passing a slurry containing monomer and solid polymer from said reaction zone to a spray drying zone, spray drying the monomer slurry to form solid polymers in monomer vapor, separating solid polymer from monomer vapor and recovering solid polymer as a product of the process and recycling part of unreacted monomer to said reaction zone.

6. A process for polymerizing triiluorochloroethylene to produce a solid polymer which comprises introducing triuorochloroethylene into one end of a horizontal elongated reaction zone maintained at a temperature between about 0 F. and about 60? F. and a pressure suicient to maintain the monomer in liquid phase, polymerizing monomer in said reaction zone to a solid polymer to form a slurry containing not more than about 12 per cent solid polymer, owing said polymer slurry through said reaction zone, removing monomer-polymer slurry from the other end of said reaction zone, passing a slurry containing monomer and solid polymer from said reaction zone to a spray drying zone, spray drying the monomer slurry to form solid polymers in monomer vapor, separating solid polymer from monomer vapor and recovering solid polymer as a product of the process.

7. A process for polymerizing trifluorochloroethylene which comprises introducing liquid triiluorochloroethylene as the monomer into one end of an elongated horizontal reaction zone, maintaining a liquid level in said reaction zone, separating that portion of the reaction zone containing liquid into a plurality of sections by means of partial baes, passing liquid monomer thus introduced between said sections at the bottom of the reaction zone such that the net movement of liquid monomer is in a substantially horizontal direction along the bottom of said reaction zone, vigorously agitating liquid monomer in each of said reaction sections of said reaction zone, polymerizing monomer in said liquid phase in said reaction zone at a temperature between about O and about 70 F. to form a slurry of solid polymer and monomer containing not more than about l2 per cent by weight of solid polymer, removing from said reaction zone vaporons triluorochloroethylene from above said liquid level, cooling and condensing said liquid vapors and returning condensate to said reaction zone whereby heat of reaction is at least partially removed by said cooling and condensing and withdrawing monomer-polymer slurry from the other end of said reaction zone.

8. A process for polymerizing tritluorochloroethylene which comprises introducing liquid triiluorochloroetliylene as the monomer into one end of an elongated horizontal reaction zone, maintaining a liquid level in said reaction zone, separating that portion of the reaction zone containing liquid into a plurality of sections by means of partial baffles, passing liquid monomer thus introduced between said sections at the bottom of the reaction zone such that the net movement of liquid monomer is in a substantially horizontal direction along the bottom of said reaction zone, vigorously agitating liquid monomer in each of said reaction sections of said reaction zone, polymerzing monomer in said liquid phase in said reaction zone to form a slurry of solid polymer and monomer containing not more than about 12 per cent by weight of solid polymer, and withdrawing monomer-polymer slurry from the other end of said reaction zone.

References Cited in the le of this patent UNITED STATES PATENTS 2,600,804 Rearick July 17, 1952 5 2,606,937 Calfee e Aug. 12, 1952 2,614,129 McBee Oct. 14, 1952 OTHER REFERENCES Norris: Experimental Organic Chemistry, pages 85 and 86, McGraw-Hill (1933). 

1. A PROCESS FOR POLYMERIZING TRIFLUOROCHLOROETHYLENE TO PRODUCE A SOLID POLYMER WHICH COMPRISES INTRODUCING TRIFLUOROCHLOROETHYLENE INTO ONE END OF A HORIZONTAL ELON GATED REACTION ZONE MAINTAINED AT A TEMPERATURE OF ABOUT 32* F. AND A PRESSURE OF ABOUT 30 POUNDS PER SQUARE INCH GAGE, POLYMERIZING MONOMER IN SAID REACTION ZONE TO SOLID POLYMER TO FORM A SLURRY CONTAINING NOT MORE THAN 12 PER CENT SOLID POLYMER, FLOWING SAID POLYMER SLURRY HORIZONTALLY THROUGH SAID REACTION ZONE, REMOVING MONOMER VAPORS FROM SAID REACTION ZONE, COOLING AND CONDENSING SAID MONOMER VAPOR THUS REMOVED AND RETURNING CONDENSATE TO SAID REACTION ZONE TO CONTROL THE TEMPERATURE THEREOF, REMOVING MONOMER-POLMER SLURRY FROM THE OTHER END OF SAID REACTION ZONE, PASSING A SLURRY CONTAINING MONOMER AND SOLID POLYMER FROM SAID REACTION ZONE TO A SPRAY DRYING ZONE, SPRAY DRYING THE MONOMER SLURRY AT A TEMPERATURE AT LEAST ABOUT 150* F. TO FORM FINELY DIVIDED SOLID POLYMER IN MONOMER VAPOR, SEPARATING SOLID POLYMER FROM MONOMER VAPOR AND RECOVERING SOLID POLYMER AS A PRODUCT OF THE PROCESS, RETURNING A PORTION OF THE AFORESAID MONOMER VAPOR TO SAID DRYING ZONE AT AN ELEVATED TEMPERATURE TO AID IN THE DRYING OF SAID SLURRY, PASSING ANOTHER PORTION OF THE AFORESAID VAPOROUS MONOMER CONTAINING ENTRAINED SOLID POLYMER TO A CONCENTRATION ZONE, IN SAID CONCENTRATION ZONE CONTACTING VAPOROUS MONOMER CONTAINING ENTRAINED SOLID POLYMER WITH LIQUID MONOMER, AND RECOVERING A LIQUID CON DENSATE CONTAINING SOLID POLYMER AND RECYCLING SAME TO SAID HORIZONTAL REACTION ZONE. 